Record of the recent ecosystemevents in lake karakel on the basisof redeposited diatom assemblages

About the authors:

Lev V. Razumovskiy, Dr. Geogr. Sci., Leading Researcher, Water Problems Institute, Russian Academy of Sciences
Vikentiy L. Razumovskiy, post-graduate student, Water Problems Institute, Russian Academy of Sciences

Abstract:

This study provides an analysis of data on diatom assemblages from bottom sediments in Lake Karakel (the Karachay–Cherkess Republic). The sediment cores for analysis were collected in the deepest parts of the lake. The method of graphical analysis of diatom assemblages was applied. We discussed perspectives of using this new method for paleoecological reconstructions. The results of isotopic dating were used. According to the structure of diatom assemblages we distinguished the periods of natural sedimentation in the lake. Several time intervals with the dominanceof redeposited processes were established. Redeposited diatom assemblages are determined by characteristic variations of taxonomic proportions. In addition,we revealed the stages of lake ecosystem restoration after mudflows and other negative impacts. For these stages the main characteristic features in the taxonomic structure of diatom assemblages were distinguished. Our results are confirmed by other methods of lake sediment analysis (geochemical and lithological methods).

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